Question

what is it called when a group of organisms of the same species are living together?
population
gathering
party
cluster
rewatch

Explanation:

In biology (a subfield of Natural Science), a population is defined as a group of organisms of the same species living in a particular area and interacting with one another. "Gathering" is a general term for a collection of things/people, "party" is a social event, and "cluster" refers to a group but not specifically for the same species in a biological context. So the correct term is population.

Answer:

A. population